This module causes an error if any nil global is read or if any global is written to, with the exception of arg. To use, add require('Module:No globals') to the top of the module using it. The arg variable is excluded because it is necessary for Scribunto's require function to work properly. (See the Scribunto source code here.)

local mt = getmetatable(_G) or {} function mt.__index (t, k) 	if k ~= 'arg' then 		error('Tried to read nil global ' .. tostring(k), 2) 	end 	return nil end function mt.__newindex(t, k, v) 	if k ~= 'arg' then 		error('Tried to write global ' .. tostring(k), 2) 	end 	rawset(t, k, v) end setmetatable(_G, mt)